(1) Field of the Invention
The present invention relates to a transmission system for a working vehicle, particularly an agricultural tractor, in which drive of an engine is transmitted to a wheel drive mechanism after being subjected to a speed change at a main transmission and an auxiliary transmission.
(2) Description of the Prior Art
In known transmission systems as noted above, the drive output by the main transmission, regardless of its speed, is transmitted to the wheel drive mechanism through the auxiliary transmission.
Where, for example, an operation in one site is completed and the vehicle should be moved to a next site of operation, it is desirable to drive the vehicle at a maximum forward speed (hereinafter referred to as overtop speed) by shifting the main transmission to a high speed position. With the known transmission system, however, the shifting of the main transmission to the high speed position does not produce the overtop speed if the auxiliary transmission is in a low speed position. In order to obtain the overtop speed it is necessary to shift the auxiliary transmission to a high speed position also. Thus it has been a troublesome operation to change the drive to the overtop speed.